builtins/set.def~

   1 This file is set.def, from which is created set.c.
   2 It implements the "set" and "unset" builtins in Bash.
   3
   4 Copyright (C) 1987-2004 Free Software Foundation, Inc.
   5
   6 This file is part of GNU Bash, the Bourne Again SHell.
   7
   8 Bash is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 Bash is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License along
  19 with Bash; see the file COPYING.  If not, write to the Free Software
  20 Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
  21
  22 $PRODUCES set.c
  23
  24 #include <config.h>
  25
  26 #if defined (HAVE_UNISTD_H)
  27 #  ifdef _MINIX
  28 #    include <sys/types.h>
  29 #  endif
  30 #  include <unistd.h>
  31 #endif
  32
  33 #include <stdio.h>
  34
  35 #include "../bashansi.h"
  36 #include "../bashintl.h"
  37
  38 #include "../shell.h"
  39 #include "../flags.h"
  40 #include "common.h"
  41 #include "bashgetopt.h"
  42
  43 #if defined (READLINE)
  44 #  include "../input.h"
  45 #  include "../bashline.h"
  46 #  include <readline/readline.h>
  47 #endif
  48
  49 #if defined (HISTORY)
  50 #  include "../bashhist.h"
  51 #endif
  52
  53 extern int posixly_correct, ignoreeof, eof_encountered_limit;
  54 #if defined (HISTORY)
  55 extern int dont_save_function_defs;
  56 #endif
  57 #if defined (READLINE)
  58 extern int no_line_editing;
  59 #endif /* READLINE */
  60
  61 $BUILTIN set
  62 $FUNCTION set_builtin
  63 $SHORT_DOC set [--abefhkmnptuvxBCHP] [-o option-name] [arg ...]
  64     -a  Mark variables which are modified or created for export.
  65     -b  Notify of job termination immediately.
  66     -e  Exit immediately if a command exits with a non-zero status.
  67     -f  Disable file name generation (globbing).
  68     -h  Remember the location of commands as they are looked up.
  69     -k  All assignment arguments are placed in the environment for a
  70         command, not just those that precede the command name.
  71     -m  Job control is enabled.
  72     -n  Read commands but do not execute them.
  73     -o option-name
  74         Set the variable corresponding to option-name:
  75             allexport    same as -a
  76             braceexpand  same as -B
  77 #if defined (READLINE)
  78             emacs        use an emacs-style line editing interface
  79 #endif /* READLINE */
  80             errexit      same as -e
  81             errtrace     same as -E
  82             functrace    same as -T
  83             hashall      same as -h
  84 #if defined (BANG_HISTORY)
  85             histexpand   same as -H
  86 #endif /* BANG_HISTORY */
  87 #if defined (HISTORY)
  88             history      enable command history
  89 #endif
  90             ignoreeof    the shell will not exit upon reading EOF
  91             interactive-comments
  92                          allow comments to appear in interactive commands
  93             keyword      same as -k
  94             monitor      same as -m
  95             noclobber    same as -C
  96             noexec       same as -n
  97             noglob       same as -f
  98             nolog        currently accepted but ignored
  99             notify       same as -b
 100             nounset      same as -u
 101             onecmd       same as -t
 102             physical     same as -P
 103             pipefail     the return value of a pipeline is the status of
 104                          the last command to exit with a non-zero status,
 105                          or zero if no command exited with a non-zero status
 106             posix        change the behavior of bash where the default
 107                          operation differs from the 1003.2 standard to
 108                          match the standard
 109             privileged   same as -p
 110             verbose      same as -v
 111 #if defined (READLINE)
 112             vi           use a vi-style line editing interface
 113 #endif /* READLINE */
 114             xtrace       same as -x
 115     -p  Turned on whenever the real and effective user ids do not match.
 116         Disables processing of the $ENV file and importing of shell
 117         functions.  Turning this option off causes the effective uid and
 118         gid to be set to the real uid and gid.
 119     -t  Exit after reading and executing one command.
 120     -u  Treat unset variables as an error when substituting.
 121     -v  Print shell input lines as they are read.
 122     -x  Print commands and their arguments as they are executed.
 123 #if defined (BRACE_EXPANSION)
 124     -B  the shell will perform brace expansion
 125 #endif /* BRACE_EXPANSION */
 126     -C  If set, disallow existing regular files to be overwritten
 127         by redirection of output.
 128     -E  If set, the ERR trap is inherited by shell functions.
 129 #if defined (BANG_HISTORY)
 130     -H  Enable ! style history substitution.  This flag is on
 131         by default when the shell is interactive.
 132 #endif /* BANG_HISTORY */
 133     -P  If set, do not follow symbolic links when executing commands
 134         such as cd which change the current directory.
 135     -T  If set, the DEBUG trap is inherited by shell functions.
 136     -   Assign any remaining arguments to the positional parameters.
 137         The -x and -v options are turned off.
 138
 139 Using + rather than - causes these flags to be turned off.  The
 140 flags can also be used upon invocation of the shell.  The current
 141 set of flags may be found in $-.  The remaining n ARGs are positional
 142 parameters and are assigned, in order, to $1, $2, .. $n.  If no
 143 ARGs are given, all shell variables are printed.
 144 $END
 145
 146 typedef int setopt_set_func_t __P((int, char *));
 147 typedef int setopt_get_func_t __P((char *));
 148
 149 static void print_minus_o_option __P((char *, int, int));
 150 static void print_all_shell_variables __P((void));
 151
 152 static int set_ignoreeof __P((int, char *));
 153 static int set_posix_mode __P((int, char *));
 154
 155 #if defined (READLINE)
 156 static int set_edit_mode __P((int, char *));
 157 static int get_edit_mode __P((char *));
 158 #endif
 159
 160 #if defined (HISTORY)
 161 static int bash_set_history __P((int, char *));
 162 #endif
 163
 164 static char *on = "on";
 165 static char *off = "off";
 166
 167 /* A struct used to match long options for set -o to the corresponding
 168    option letter or internal variable.  The functions can be called to
 169    dynamically generate values. */
 170 struct {
 171   char *name;
 172   int letter;
 173   int *variable;
 174   setopt_set_func_t *set_func;
 175   setopt_get_func_t *get_func;
 176 } o_options[] = {
 177   { "allexport",  'a', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL },
 178 #if defined (BRACE_EXPANSION)
 179   { "braceexpand",'B', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 180 #endif
 181 #if defined (READLINE)
 182   { "emacs",     '\0', (int *)NULL, set_edit_mode, get_edit_mode },
 183 #endif
 184   { "errexit",    'e', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 185   { "errtrace",   'E', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 186   { "functrace",  'T', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 187   { "hashall",    'h', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 188 #if defined (BANG_HISTORY)
 189   { "histexpand", 'H', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 190 #endif /* BANG_HISTORY */
 191 #if defined (HISTORY)
 192   { "history",   '\0', &remember_on_history, bash_set_history, (setopt_get_func_t *)NULL },
 193 #endif
 194   { "ignoreeof", '\0', &ignoreeof, set_ignoreeof, (setopt_get_func_t *)NULL },
 195   { "interactive-comments", '\0', &interactive_comments, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL },
 196   { "keyword",    'k', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 197   { "monitor",    'm', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 198   { "noclobber",  'C', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 199   { "noexec",     'n', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 200   { "noglob",     'f', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 201 #if defined (HISTORY)
 202   { "nolog",     '\0', &dont_save_function_defs, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL },
 203 #endif
 204 #if defined (JOB_CONTROL)
 205   { "notify",     'b', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 206 #endif /* JOB_CONTROL */
 207   { "nounset",    'u', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 208   { "onecmd",     't', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL },
 209   { "physical",   'P', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 210   { "pipefail",  '\0', &pipefail_opt, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 211   { "posix",     '\0', &posixly_correct, set_posix_mode, (setopt_get_func_t *)NULL },
 212   { "privileged", 'p', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 213   { "verbose",    'v', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 214 #if defined (READLINE)
 215   { "vi",        '\0', (int *)NULL, set_edit_mode, get_edit_mode },
 216 #endif
 217   { "xtrace",     'x', (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL  },
 218   {(char *)NULL, 0 , (int *)NULL, (setopt_set_func_t *)NULL, (setopt_get_func_t *)NULL },
 219 };
 220
 221 #define N_O_OPTIONS     (sizeof (o_options) / sizeof (o_options[0]))
 222
 223 #define GET_BINARY_O_OPTION_VALUE(i, name) \
 224   ((o_options[i].get_func) ? (*o_options[i].get_func) (name) \
 225                            : (*o_options[i].variable))
 226
 227 #define SET_BINARY_O_OPTION_VALUE(i, onoff, name) \
 228   ((o_options[i].set_func) ? (*o_options[i].set_func) (onoff, name) \
 229                            : (*o_options[i].variable = (onoff == FLAG_ON)))
 230
 231 int
 232 minus_o_option_value (name)
 233      char *name;
 234 {
 235   register int  i;
 236   int *on_or_off;
 237
 238   for (i = 0; o_options[i].name; i++)
 239     {
 240       if (STREQ (name, o_options[i].name))
 241         {
 242           if (o_options[i].letter)
 243             {
 244               on_or_off = find_flag (o_options[i].letter);
 245               return ((on_or_off == FLAG_UNKNOWN) ? -1 : *on_or_off);
 246             }
 247           else
 248             return (GET_BINARY_O_OPTION_VALUE (i, name));
 249         }
 250     }
 251
 252   return (-1);
 253 }
 254
 255 #define MINUS_O_FORMAT "%-15s\t%s\n"
 256
 257 static void
 258 print_minus_o_option (name, value, pflag)
 259      char *name;
 260      int value, pflag;
 261 {
 262   if (pflag == 0)
 263     printf (MINUS_O_FORMAT, name, value ? on : off);
 264   else
 265     printf ("set %co %s\n", value ? '-' : '+', name);
 266 }
 267
 268 void
 269 list_minus_o_opts (mode, reusable)
 270      int mode, reusable;
 271 {
 272   register int  i;
 273   int *on_or_off, value;
 274
 275   for (i = 0; o_options[i].name; i++)
 276     {
 277       if (o_options[i].letter)
 278         {
 279           value = 0;
 280           on_or_off = find_flag (o_options[i].letter);
 281           if (on_or_off == FLAG_UNKNOWN)
 282             on_or_off = &value;
 283           if (mode == -1 || mode == *on_or_off)
 284             print_minus_o_option (o_options[i].name, *on_or_off, reusable);
 285         }
 286       else
 287         {
 288           value = GET_BINARY_O_OPTION_VALUE (i, o_options[i].name);
 289           if (mode == -1 || mode == value)
 290             print_minus_o_option (o_options[i].name, value, reusable);
 291         }
 292     }
 293 }
 294
 295 char **
 296 get_minus_o_opts ()
 297 {
 298   char **ret;
 299   int i;
 300
 301   ret = strvec_create (N_O_OPTIONS + 1);
 302   for (i = 0; o_options[i].name; i++)
 303     ret[i] = o_options[i].name;
 304   ret[i] = (char *)NULL;
 305   return ret;
 306 }
 307
 308 static int
 309 set_ignoreeof (on_or_off, option_name)
 310      int on_or_off;
 311      char *option_name;
 312 {
 313   ignoreeof = on_or_off == FLAG_ON;
 314   unbind_variable ("ignoreeof");
 315   if (ignoreeof)
 316     bind_variable ("IGNOREEOF", "10", 0);
 317   else
 318     unbind_variable ("IGNOREEOF");
 319   sv_ignoreeof ("IGNOREEOF");
 320   return 0;
 321 }
 322
 323 static int
 324 set_posix_mode (on_or_off, option_name)
 325      int on_or_off;
 326      char *option_name;
 327 {
 328   posixly_correct = on_or_off == FLAG_ON;
 329   if (posixly_correct == 0)
 330     unbind_variable ("POSIXLY_CORRECT");
 331   else
 332     bind_variable ("POSIXLY_CORRECT", "y", 0);
 333   sv_strict_posix ("POSIXLY_CORRECT");
 334   return (0);
 335 }
 336
 337 #if defined (READLINE)
 338 /* Magic.  This code `knows' how readline handles rl_editing_mode. */
 339 static int
 340 set_edit_mode (on_or_off, option_name)
 341      int on_or_off;
 342      char *option_name;
 343 {
 344   int isemacs;
 345
 346   if (on_or_off == FLAG_ON)
 347     {
 348       rl_variable_bind ("editing-mode", option_name);
 349
 350       if (interactive)
 351         with_input_from_stdin ();
 352       no_line_editing = 0;
 353     }
 354   else
 355     {
 356       isemacs = rl_editing_mode == 1;
 357       if ((isemacs && *option_name == 'e') || (!isemacs && *option_name == 'v'))
 358         {
 359           if (interactive)
 360             with_input_from_stream (stdin, "stdin");
 361           no_line_editing = 1;
 362         }
 363     }
 364   return 1-no_line_editing;
 365 }
 366
 367 static int
 368 get_edit_mode (name)
 369      char *name;
 370 {
 371   return (*name == 'e' ? no_line_editing == 0 && rl_editing_mode == 1
 372                        : no_line_editing == 0 && rl_editing_mode == 0);
 373 }
 374 #endif /* READLINE */
 375
 376 #if defined (HISTORY)
 377 static int
 378 bash_set_history (on_or_off, option_name)
 379      int on_or_off;
 380      char *option_name;
 381 {
 382   if (on_or_off == FLAG_ON)
 383     {
 384       bash_history_enable ();
 385       if (history_lines_this_session == 0)
 386         load_history ();
 387     }
 388   else
 389     bash_history_disable ();
 390   return (1 - remember_on_history);
 391 }
 392 #endif
 393
 394 int
 395 set_minus_o_option (on_or_off, option_name)
 396      int on_or_off;
 397      char *option_name;
 398 {
 399   register int i;
 400
 401   for (i = 0; o_options[i].name; i++)
 402     {
 403       if (STREQ (option_name, o_options[i].name))
 404         {
 405           if (o_options[i].letter == 0)
 406             {
 407               SET_BINARY_O_OPTION_VALUE (i, on_or_off, option_name);
 408               return (EXECUTION_SUCCESS);
 409             }
 410           else
 411             {
 412               if (change_flag (o_options[i].letter, on_or_off) == FLAG_ERROR)
 413                 {
 414                   sh_invalidoptname (option_name);
 415                   return (EXECUTION_FAILURE);
 416                 }
 417               else
 418                 return (EXECUTION_SUCCESS);
 419             }
 420
 421         }
 422     }
 423
 424   sh_invalidoptname (option_name);
 425   return (EXECUTION_FAILURE);
 426 }
 427
 428 static void
 429 print_all_shell_variables ()
 430 {
 431   SHELL_VAR **vars;
 432
 433   vars = all_shell_variables ();
 434   if (vars)
 435     {
 436       print_var_list (vars);
 437       free (vars);
 438     }
 439
 440   /* POSIX.2 does not allow function names and definitions to be output when
 441      `set' is invoked without options (PASC Interp #202). */
 442   if (posixly_correct == 0)
 443     {
 444       vars = all_shell_functions ();
 445       if (vars)
 446         {
 447           print_func_list (vars);
 448           free (vars);
 449         }
 450     }
 451 }
 452
 453 void
 454 set_shellopts ()
 455 {
 456   char *value;
 457   char tflag[N_O_OPTIONS];
 458   int vsize, i, vptr, *ip, exported;
 459   SHELL_VAR *v;
 460
 461   for (vsize = i = 0; o_options[i].name; i++)
 462     {
 463       tflag[i] = 0;
 464       if (o_options[i].letter)
 465         {
 466           ip = find_flag (o_options[i].letter);
 467           if (ip && *ip)
 468             {
 469               vsize += strlen (o_options[i].name) + 1;
 470               tflag[i] = 1;
 471             }
 472         }
 473       else if (GET_BINARY_O_OPTION_VALUE (i, o_options[i].name))
 474         {
 475           vsize += strlen (o_options[i].name) + 1;
 476           tflag[i] = 1;
 477         }
 478     }
 479
 480   value = (char *)xmalloc (vsize + 1);
 481
 482   for (i = vptr = 0; o_options[i].name; i++)
 483     {
 484       if (tflag[i])
 485         {
 486           strcpy (value + vptr, o_options[i].name);
 487           vptr += strlen (o_options[i].name);
 488           value[vptr++] = ':';
 489         }
 490     }
 491
 492   if (vptr)
 493     vptr--;                     /* cut off trailing colon */
 494   value[vptr] = '\0';
 495
 496   v = find_variable ("SHELLOPTS");
 497
 498   /* Turn off the read-only attribute so we can bind the new value, and
 499      note whether or not the variable was exported. */
 500   if (v)
 501     {
 502       VUNSETATTR (v, att_readonly);
 503       exported = exported_p (v);
 504     }
 505   else
 506     exported = 0;
 507
 508   v = bind_variable ("SHELLOPTS", value, 0);
 509
 510   /* Turn the read-only attribute back on, and turn off the export attribute
 511      if it was set implicitly by mark_modified_vars and SHELLOPTS was not
 512      exported before we bound the new value. */
 513   VSETATTR (v, att_readonly);
 514   if (mark_modified_vars && exported == 0 && exported_p (v))
 515     VUNSETATTR (v, att_exported);
 516
 517   free (value);
 518 }
 519
 520 void
 521 parse_shellopts (value)
 522      char *value;
 523 {
 524   char *vname;
 525   int vptr;
 526
 527   vptr = 0;
 528   while (vname = extract_colon_unit (value, &vptr))
 529     {
 530       set_minus_o_option (FLAG_ON, vname);
 531       free (vname);
 532     }
 533 }
 534
 535 void
 536 initialize_shell_options (no_shellopts)
 537      int no_shellopts;
 538 {
 539   char *temp;
 540   SHELL_VAR *var;
 541
 542   if (no_shellopts == 0)
 543     {
 544       var = find_variable ("SHELLOPTS");
 545       /* set up any shell options we may have inherited. */
 546       if (var && imported_p (var))
 547         {
 548           temp = (array_p (var)) ? (char *)NULL : savestring (value_cell (var));
 549           if (temp)
 550             {
 551               parse_shellopts (temp);
 552               free (temp);
 553             }
 554         }
 555     }
 556
 557   /* Set up the $SHELLOPTS variable. */
 558   set_shellopts ();
 559 }
 560
 561 /* Reset the values of the -o options that are not also shell flags.  This is
 562    called from execute_cmd.c:initialize_subshell() when setting up a subshell
 563    to run an executable shell script without a leading `#!'. */
 564 void
 565 reset_shell_options ()
 566 {
 567 #if defined (HISTORY)
 568   remember_on_history = 1;
 569 #endif
 570   ignoreeof = 0;
 571 }
 572
 573 /* Set some flags from the word values in the input list.  If LIST is empty,
 574    then print out the values of the variables instead.  If LIST contains
 575    non-flags, then set $1 - $9 to the successive words of LIST. */
 576 int
 577 set_builtin (list)
 578      WORD_LIST *list;
 579 {
 580   int on_or_off, flag_name, force_assignment, opts_changed;
 581   register char *arg;
 582   char s[3];
 583
 584   if (list == 0)
 585     {
 586       print_all_shell_variables ();
 587       return (EXECUTION_SUCCESS);
 588     }
 589
 590   /* Check validity of flag arguments. */
 591   reset_internal_getopt ();
 592   while ((flag_name = internal_getopt (list, optflags)) != -1)
 593     {
 594       switch (flag_name)
 595         {
 596           case '?':
 597             builtin_usage ();
 598             return (list_optopt == '?' ? EXECUTION_SUCCESS : EX_USAGE);
 599           default:
 600             break;
 601         }
 602     }
 603
 604   /* Do the set command.  While the list consists of words starting with
 605      '-' or '+' treat them as flags, otherwise, start assigning them to
 606      $1 ... $n. */
 607   for (force_assignment = opts_changed = 0; list; )
 608     {
 609       arg = list->word->word;
 610
 611       /* If the argument is `--' or `-' then signal the end of the list
 612          and remember the remaining arguments. */
 613       if (arg[0] == '-' && (!arg[1] || (arg[1] == '-' && !arg[2])))
 614         {
 615           list = list->next;
 616
 617           /* `set --' unsets the positional parameters. */
 618           if (arg[1] == '-')
 619             force_assignment = 1;
 620
 621           /* Until told differently, the old shell behaviour of
 622              `set - [arg ...]' being equivalent to `set +xv [arg ...]'
 623              stands.  Posix.2 says the behaviour is marked as obsolescent. */
 624           else
 625             {
 626               change_flag ('x', '+');
 627               change_flag ('v', '+');
 628               opts_changed = 1;
 629             }
 630
 631           break;
 632         }
 633
 634       if ((on_or_off = *arg) && (on_or_off == '-' || on_or_off == '+'))
 635         {
 636           while (flag_name = *++arg)
 637             {
 638               if (flag_name == '?')
 639                 {
 640                   builtin_usage ();
 641                   return (EXECUTION_SUCCESS);
 642                 }
 643               else if (flag_name == 'o') /* -+o option-name */
 644                 {
 645                   char *option_name;
 646                   WORD_LIST *opt;
 647
 648                   opt = list->next;
 649
 650                   if (opt == 0)
 651                     {
 652                       list_minus_o_opts (-1, (on_or_off == '+'));
 653                       continue;
 654                     }
 655
 656                   option_name = opt->word->word;
 657
 658                   if (option_name == 0 || *option_name == '\0' ||
 659                       *option_name == '-' || *option_name == '+')
 660                     {
 661                       list_minus_o_opts (-1, (on_or_off == '+'));
 662                       continue;
 663                     }
 664                   list = list->next; /* Skip over option name. */
 665
 666                   opts_changed = 1;
 667                   if (set_minus_o_option (on_or_off, option_name) != EXECUTION_SUCCESS)
 668                     {
 669                       set_shellopts ();
 670                       return (EXECUTION_FAILURE);
 671                     }
 672                 }
 673               else if (change_flag (flag_name, on_or_off) == FLAG_ERROR)
 674                 {
 675                   s[0] = on_or_off;
 676                   s[1] = flag_name;
 677                   s[2] = '\0';
 678                   sh_invalidopt (s);
 679                   builtin_usage ();
 680                   set_shellopts ();
 681                   return (EXECUTION_FAILURE);
 682                 }
 683               opts_changed = 1;
 684             }
 685         }
 686       else
 687         {
 688           break;
 689         }
 690       list = list->next;
 691     }
 692
 693   /* Assigning $1 ... $n */
 694   if (list || force_assignment)
 695     remember_args (list, 1);
 696   /* Set up new value of $SHELLOPTS */
 697   if (opts_changed)
 698     set_shellopts ();
 699   return (EXECUTION_SUCCESS);
 700 }
 701
 702 $BUILTIN unset
 703 $FUNCTION unset_builtin
 704 $SHORT_DOC unset [-f] [-v] [name ...]
 705 For each NAME, remove the corresponding variable or function.  Given
 706 the `-v', unset will only act on variables.  Given the `-f' flag,
 707 unset will only act on functions.  With neither flag, unset first
 708 tries to unset a variable, and if that fails, then tries to unset a
 709 function.  Some variables cannot be unset; also see readonly.
 710 $END
 711
 712 #define NEXT_VARIABLE() any_failed++; list = list->next; continue;
 713
 714 int
 715 unset_builtin (list)
 716   WORD_LIST *list;
 717 {
 718   int unset_function, unset_variable, unset_array, opt, any_failed;
 719   char *name;
 720
 721   unset_function = unset_variable = unset_array = any_failed = 0;
 722
 723   reset_internal_getopt ();
 724   while ((opt = internal_getopt (list, "fv")) != -1)
 725     {
 726       switch (opt)
 727         {
 728         case 'f':
 729           unset_function = 1;
 730           break;
 731         case 'v':
 732           unset_variable = 1;
 733           break;
 734         default:
 735           builtin_usage ();
 736           return (EX_USAGE);
 737         }
 738     }
 739
 740   list = loptend;
 741
 742   if (unset_function && unset_variable)
 743     {
 744       builtin_error (_("cannot simultaneously unset a function and a variable"));
 745       return (EXECUTION_FAILURE);
 746     }
 747
 748   while (list)
 749     {
 750       SHELL_VAR *var;
 751       int tem;
 752 #if defined (ARRAY_VARS)
 753       char *t;
 754 #endif
 755
 756       name = list->word->word;
 757
 758 #if defined (ARRAY_VARS)
 759       unset_array = 0;
 760       if (!unset_function && valid_array_reference (name))
 761         {
 762           t = strchr (name, '[');
 763           *t++ = '\0';
 764           unset_array++;
 765         }
 766 #endif
 767
 768       /* Bash allows functions with names which are not valid identifiers
 769          to be created when not in posix mode, so check only when in posix
 770          mode when unsetting a function. */
 771       if (((unset_function && posixly_correct) || !unset_function) && legal_identifier (name) == 0)
 772         {
 773           sh_invalidid (name);
 774           NEXT_VARIABLE ();
 775         }
 776
 777       var = unset_function ? find_function (name) : find_variable (name);
 778
 779       if (var && !unset_function && non_unsettable_p (var))
 780         {
 781           builtin_error (_("%s: cannot unset"), name);
 782           NEXT_VARIABLE ();
 783         }
 784
 785       /* Posix.2 says that unsetting readonly variables is an error. */
 786       if (var && readonly_p (var))
 787         {
 788           builtin_error (_("%s: cannot unset: readonly %s"),
 789                          name, unset_function ? "function" : "variable");
 790           NEXT_VARIABLE ();
 791         }
 792
 793       /* Unless the -f option is supplied, the name refers to a variable. */
 794 #if defined (ARRAY_VARS)
 795       if (var && unset_array)
 796         {
 797           if (array_p (var) == 0)
 798             {
 799               builtin_error (_("%s: not an array variable"), name);
 800               NEXT_VARIABLE ();
 801             }
 802           else
 803             {
 804               tem = unbind_array_element (var, t);
 805               if (tem == -1)
 806                 any_failed++;
 807             }
 808         }
 809       else
 810 #endif /* ARRAY_VARS */
 811       tem = unset_function ? unbind_func (name) : unbind_variable (name);
 812
 813       /* This is what Posix.2 draft 11+ says.  ``If neither -f nor -v
 814          is specified, the name refers to a variable; if a variable by
 815          that name does not exist, a function by that name, if any,
 816          shall be unset.'' */
 817       if (tem == -1 && !unset_function && !unset_variable)
 818         tem = unbind_func (name);
 819
 820       /* SUSv3, POSIX.1-2001 say:  ``Unsetting a variable or function that
 821          was not previously set shall not be considered an error.'' */
 822
 823       if (unset_function == 0)
 824         stupidly_hack_special_variables (name);
 825
 826       list = list->next;
 827     }
 828
 829   return (any_failed ? EXECUTION_FAILURE : EXECUTION_SUCCESS);
 830 }